The main goal in Matte Painting is to create a photorealistic picture to seamlessly blend
with the rest of the footage. You may use 2D, 3D, Painting, Photo or any combination or trick as long as itís believable.All that producers or VFX supervisors want is that to produce
the matte painting faster and more believable.The common sense; when you mixing things
together is to watch for light direction, Black Levels, Perspective and scale of different elements.

There is also an interesting answer on how to become a Digital Matte Painter at: www.guerillapixel.com/pages/digital_ill_main.htm

Also check out the tutorials and available DVDs.

In this scene Stargate digital has used a combination of 2D, 3D and 2-1/2D